Towards UAV-Based Ultra-Wideband Multi-Baseline SAR Interferometry

Abstract

Unmanned Aerial Vehicle (UAV)-based synthetic aperture radar (SAR) systems enable very accurate and cost-effective monitoring of local areas with unprecedentedly short revisit intervals. This paper discusses specific aspects that arise in the context of UAV-based multi-baseline SAR interferometry (InSAR) for the generation of digital elevation models (DEMs). UAV-based SAR systems are often characterized by a large fractional bandwidth, thus the common narrowband spaceborne approximations yield inaccurate predictions for the geometric decorrelation and the critical baseline. A new formulation is proposed and validated by simulation. Based on the theoretical analyses, a multi-baseline InSAR experiment is planned. The DEM performance analysis shows that large baselines enable height accuracies in the sub-decimeter range, where geometric and volume decorrelation become the limiting factors. This paves the way to height measurements with unprecedented accuracy for multiple applications.